target/riscv/cpu.c: validate extensions before riscv_timer_init()

There is no need to init timers if we're not even sure that our
extensions are valid. Execute riscv_cpu_validate_set_extensions() before
riscv_timer_init().

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20230517135714.211809-10-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.c

@@ -1294,20 +1294,17 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
         return;
     }
 
-
-#ifndef CONFIG_USER_ONLY
-    if (cpu->cfg.ext_sstc) {
-        riscv_timer_init(cpu);
-    }
-#endif /* CONFIG_USER_ONLY */
-
     riscv_cpu_validate_set_extensions(cpu, &local_err);
     if (local_err != NULL) {
         error_propagate(errp, local_err);
         return;
     }
 
 #ifndef CONFIG_USER_ONLY
+    if (cpu->cfg.ext_sstc) {
+        riscv_timer_init(cpu);
+    }
+
     if (cpu->cfg.pmu_num) {
         if (!riscv_pmu_init(cpu, cpu->cfg.pmu_num) && cpu->cfg.ext_sscofpmf) {
             cpu->pmu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,